Balloon. A globe made of silk, and rendered air-tight by gum, which, when filled with hydrogen gas, from 10 to 13 times lighter than atmospherical air, ascends into the atmosphere, and will convey heavy bodies suspended to it. The ascent in a balloon is a magnificent spectacle; but, owing to mismanagement. they have often produced fatal accidents. The first balloon ascended at Paris, in 1782: and in London, in 1784.